If i have slight symptoms of a yeast infection and after intercourse the symptoms become major have i infected my partner or should i treat myself otc?

Treat both of you: Both of you need to be treated. Guys can get yeast infections, too. If you aren't both treated then you can pass the infection back and forth and cause real problems.

Yes: You can treat yourself w/any otc preparation. I like a 7better day course better, however, they should all be fairly equally effective. As far as your partner goes, most physicians will not treat the partner, as it is thought that only women develop yeast infection, however, i've seen growing opinions of the fact that partners may harbor yeast and eventually reinfect their female partners.